Clutch mechanism



Sept. 23, 1941. J; DARBY. 2,256,826

CLUTCH MECHANISM Filed Nov.A 10, 1959 2 sheets-sheet 1 Sept. 23, 1941. J. DARBY CLUTCH MECHANISM Filed Nov. lO, 1959 2 Sheets-Sheet 2 1N VNTOR.

ATTORNEY Patented Sept. 1941 UNITED STATES PATENT oFFlcE My invention relates to improvements in mechanical movements.

In order to reduce unit stress in vehicle running gear, it is customary practice to equip vehicles of certain types such as trucks, buses and the like with multiple wheel Dual wheel units are commonly employed although units embodying more than two wheels have been s d are used.

Multiple wheel units present certain practical difficulties since the wheels in their side by side relationship must follow paths respectively having different radii of curvature when the vehicle is guided along a curved course. Unless the construction of the unit is such that its wheels may rotate relative to each other in such a case, undue tire wear will result and power requirements are excessive. Divers types of multiple wheel units have -been proposed. They have in many cases proven satisfactory particularly where the wheels are relatively rotatable but are not power driven. However, it is almost uniform practice to couple the wheels of the unit forrotation togetherl when they must function as driving wheels. The various expedients heretofore suggested as a solution to the problem of combining in a multiple wheel unit among other things the desirable features of power drive and relative rotatability of the wheels have not proven satisfactory to my knowledge.

An object of my invention therefore is to provide a novel multiple wheel unit.

Another object of my invention is to provide a novel wheel braking system for such a unit.

Another object of my invention is to provide a multiple wheel unit, any one of whose wheel elements may be power driven in a forward or reverse direction while another of the wheel elements is rotating relative thereto.

Another object of my invention is to provide a novel coupling device which is capable of transeither direction of rotation, into releasable torque transmitting engagement with one or more rotatably mounted driven elements. Further, in accomplishing the objects of my invention, I so construct and arrange the clutch mechanism that engagement of the driven element or elements by the clutch mechanism will continue only so long as the driving element transmits torque therethrough to the driven element or elements. Upon cessation of torque transmission, the clutch mechanism will automatically release itself from engagement with the driven element or elements permitting thev latter to rotate relative to the driving element at a rate subject to control by the braking system emi The clutch mechanism employed 'comprises a locking member or members each pivotally mounted upon the driving element or a suitable extension thereof for rotation therewith and for limited yieldingly opposed angular movement relative thereto, in response to the effects of centrifugal force and inertia, upon a pivotal axis positioned outwardly of the center of mass or gravity of the locking member.

The locking member or members, if more than one be utilized, engages, upon angular displacement, a suitably contoured surface of the'driven'y element, or elements if there be more than one, thereby establishinga locking or driving connection with the element engaged enabling the driving element to rotate the driven element about its axis. For the accomplishment of this purpose, each suchlocking member is formed withv a suitable engaging surface contoured to provide the desired type of locking engagement with the driven element. The engaging surfaces mitting torque from one element to the other element of a pair of rotatably mounted elements to eiect clockwise or counterclockwise movement of said elements as a unit, but which is incapable normally of-transmitting torque from thelatter to the former.

Other and further objects of my invention will of the respective locking members and of the driven element are preferably formed to provide a wedge-friction type of locking engagement, the intensity of which is proportional to the driving force or torque being transmitted. The yengaging surfaces may be formed if desired, how- \ever, to provide positive interlocking as, for example, by 'forming the engaged surface of thev driven element as a rack to be engaged by a locking member in the form of a symmetrical pawl. In the former case the greater the displacement of the locking member about its pivotal axis, the greater will be the intensity of the locking action' between the locking member and the driven element or, in eflect, between the driven element and the driving or torque-applying element. f This engagement and consequent guiar acceleration of the driving element in locking action will follow upon angular displace.

. views:

. Fig. 1 is a view in elevation with parts in section taken along the line I-I of Fig. 2 showing a so-called dual wheel unit embodying the clutching or couplingmechanism and the braking system of myinvention;

Fig. 2 is a view in elevationltaken along the line 2`2 of Fig. 1 showing the manner in which the locking members are arranged upon the carrying or driving disc and showing the braking elements for the outer wheel;

Fig. 3 is a view taken along the line 3-3 of Fig. 4 showing details of the driving disc and locking members; n

Fig. 4 is a fragmentary view in elevation with parts insection taken along the line 4-4 of Fig. 3 showing details ofthe coupling or clutching mechanism;

shrunk on the respective hubs being accommodated within suitable annular recesses thereof as is best shown in Fig. 4.

The driving disc I4 is pierced to provide a number of openings, each accommodating a shaft 32 upon which is journalled for limited angular movement a pair of hardened steel locking members 33 and 34 respectively positioned at either side of the drivingl disc I4.

The axis of each shaft 32 is located on a circle concentric with the axis of the driving disc I4,

the respective shaft axes being spaced equall arcuate distances from each other and being parallel to the common axis of the axle I0 and driving disc I4.

Each shaft 32 is keyed to the driving disc I4 and isl formed with a head 35 between which and 'the driving disc I4 is .located a porous bronze The shaft 32 is preferably axially drilled, as

Fig. 5 is a plan view showing a detail of the tour and has extended therefrom an annular driving disc I4 is splined or otherwise xedly secured to the axle I0 for rotation therewith and is locked 'lin position by means of a cotter-pinned castellated nut and washer assembly I5.

A pair of driven elements constituted by wheels I6 and I1 is journalled through the wheel hubs 2| and- 25 respectively upon bronze sleeve bushings I8 and I8 respectively tted upon the sleeve member I3 at either side of the driving disc I4. Thus, it will be observed that the wheel I6 is confined for rotation upon the bushing I3 between the driving disc |4 and a retaining member 20 threadedly engaging the sleeve member I3. Axial thrust of the wheel I6 is imparted to -an annular bronze thrust bearing 22. interposed between the retaining member 23 and the wheel hub 2| and to an annular bronze thrust bearing 23 interposed between the driving disc I4 and the wheel hub 2|. Similarly, axial thrust of the wheel 4I1 is imparted to an annular bronze thrust bearing 24 interposed between the driving disc I4 and the'hub 25 ofthe wheel I1 and to an annular bronze thrust* bearing 26 interposed between the hub 25 and the roller bearing A passageway 21 formed in the sleeve member `oi' the journal bolts 46 and 49.

shown, to provide a passageway 4I) through which lubricant may flow to the inner surface of the porous bushings 36 and 39 from the passageway 21 via the connecting passageway 4I in the driving -discl I4. The passageways- 40 and 4| are capped by the threaded elements 42 and 43 respectively.

A coupling ring 44 concentric with the axis of the axlev III and having radially arranged slots 45 is loosely secured to the locking members 33 by means of the headed journal bolts 46. Similarly, a coupling ring 41 concentric with the axis of the axle I0 and having radially arranged slots 46 is loosely secured tothe locking members 34 by means of the headed jour'nalxbolts 49. The slots 45 and 43 are each preferably formed with parallel side walls throughout the major portion of their length. These side walls are spaced from each other a distance equal to, or at the most..

slightly greater than the diameter of the portion lConsequently, angular movement of any one of the locking members 33 will be imparted equally by the coupling vring 44 to all of the locking members 33 andA angular movement of any one of the locking members 34 will be equally imparted by the coupling ring 41 to all of the locking members 34. v A number of pins 50 whose ends are slotted l are fitted within suitable openings in the driving disc |4 which are arranged in a circle concentric with the axis of the driving disc. The pins 56 extend equal distances outwardly from the opposite faces of the driving disc and are spaced equal arcuatev distances from each other.

In Fig. 3, I have shown flexible resilient members 5| each secured at one end to a slotted pin 50 and extending radially inwardly therefrom toward the center of the coupling ring -44. 'The other end of each resilient member 5I is slidably fitted within one o f a corresponding number of recesses 32 formed within the coupling ring 44.

.The recesses 52 are' preferably characterized by a contour such that angular movement of the coupling ring in either'direction will not inte.'-

fere with retraction andprojection of each resilient member from and'into its recess consequent upon such angular movement. Although I have shown in Fig. 3 the relationship as it exists between the resilient members 5I and the coupling ring 44, it is to be understood, however, that the construction and arrangement thereof is duplica-ted with respect. to the coupling ring 41.

The locking members 33 and 34 have cam faces or surfaces 53 and 54 which in the neutral position of the locking members are slightly spaced from the adjacent surface of the clutch rings 30 and 3| respectively. In addition, each cam face has a radius of curvature R1 greater than the radius of curvature R2 of the circle of oscillation of each locking member. Accordingly, and referring to Fig. 3, if la locking member 33, for example, is angularly displaced clockwise or counterclockwise from a neutral position about the axis of the shaft 32, its cam surface 53 will come into contact with the clutch ring 30 by reason of the difference in the radii of curvature of the cam surface 53 and the circle of oscillation of the locking member. A wedging or locking action between the locking member and the clutch ring will result rendering transmission of torque from the driving axle tothe wheel hub possible.

The construction above described is such that the axle I0 will during rectilinear movement drive both of the wheels I6 and l1 as a unit in either a forward or a reverse direc-tion. On the other hand, if the conditions be such as to require that either wheel should rotate more rapidly than the other or should rotate more slowly than the other during clockwise or counterclockwise movement, it may do so.

When the wheels are at rest and no power is applied to the driving axle I0, all the` locking members take the neutral posi-tion shown in solid outline in Fig. 3. In this position, the cam surfaces 53. for example, will be wholly out of contact with the steel ring 30. They are normally maintained in this neutral disengaged position ring 30 to come into contact with each other with a resultant locking or wedging action, they placement of .the locking members 33 and 34 will by the action of the resilient members or fingers Y 5I acting through the coupling ring 44 on th'e respective locking members 33.

As the axle I0 is set in motion and caused to rotate on itsV axis, it carries with it the sleeve member I3 of which the driving disc I4 forms a part. However, the locking members 33, for example, by reason of the eccentricity of their centers of mass and suspension willfbe subjected to inertia forces in proportion to the angular acceleration of the driving disc, resulting in an angular displacement of each u Ylocking member 33 about the axis of its supporting shaft 32. This resultant condition is best .illustrated in Fig. 3 wherein rotation of the driving disc I4 in a counter-clockwise direction would result .in a displacement of each of the locking members 33 (and of the cam members 34) to the .dotted line engaged position shown for a single cam. The locking members 33 and the locking members 34.being coupledI together by means of the rings 44 and 41 respectively will be moved equal angular distances about their respective axes of suspension. The movement which is thus imparted to the ring 44 is communicated thereby to the resilient members 5I displacing them from their neutral position to 'a dotted line position such as is 4shown .for Va single member in Fig. 3. Since the cam surface 53 of a locking member 33, for example, has a radius of curvature greater than that of the circle of oscillation of its locking member, the angular displacement of the locking member 33 will cause the cam surface 53 and the adjacent clutch be locked to the hubs 2l and 25 of the Wheels I6 and I1 respectively thereby to cause the wheels and axle to rotate as a unit. The formation of each surface about an axis of symmetry and the mode of suspension of the cam member permits the attainment of this result in either direction of rotation of the axle Il! so that positive driving of the wheels may be achieved in either a clockwise or a counter-clockwise direction of rotation.A

In the event that the wheels are directed from a rectilinear into a curvilinear path as would occur, forv example, with a vehicle following the curve of a road, the construction is such that the transmission of torque from the axle to that wheel whichA must rotate more rapidly in following the curved vpath ceases automatically. Thus,

` if the wheel assembly shown in Fig. 1 were caused to follow a curved path to the right, the wheel I6 will be caused to rotate more rapidly than the ring 30 is relieved, allowing the ring 30 and wheel I6 to slide relatively to the driving cam members 33, which nevertheless are maintained in contact with the ring 30 by the combined action of centrifugal force and inertia, ready to cause driving reengagement when the angular. velocity of driving element I3 tends to exceed that of the Wheel It is apparent that the action of the cams 33 and 34 is the same in either direction. As a result, the wheels I6 and I1 may b e driven together as a unit; one may rotate relative to the other as they follow a curvilinear path; they may rotate relative to the axle I0 and to each other when no power is applied thereto from the axle; and they may rotate relative to the axle or relative to each other where the power 'applied to the axle is insuficient to eifect angular rotation I locking members, fewer locking members and corspectivelyA whose other ends are hingedly con-f flangesA 8 and 9 respectively of the wheels I6 and I1 respectively are adapted to be engaged at will by suitable braking elements actuatable through a novel braking system, all as hereinafter more particularly described.v

Brake shoe mounting posts 62 and 63 aflixed to the wheel flange 9 and rotatable therewith have hingedly secured thereto by means of nuts 54 and 65 respectively, lined brake shoes 66 and 61 renected by means of a retractor spring 68.

Links 69 and 10 hingedly connect'the brake shoes 66 and 61 respectively and a brake shoe spreader member 1l.

vA bell crank member 12 journaled on a shaft 13 aixed to the-wheel flange 9 has one arm 14 hingedly connected to the spreader member 1| and has its other arm 15 extending radially inwardly substantially parallel to the plane of the wheel ilange 9.

A bell crank actuating ring 16 having antifriction rollers 11 Journaled therein is carried by the wheel ilange 9 for movement reciprocally of the axle 8 and in concentric relation thereto upon pins 18 slidably received in correspondingly located openings in the wheel ange 9.

A bell crank actuating pin 88 extends laterally from the ring 16 through the wheel ange 9 into engagement with the arm 15 of the bell crank member 12.

One end of each pin 18 is threaded, the thread ends being engaged by nuts 8| adjustable to limit the inward movement of the ring 16. Helical springs 82 encompassing the pins 18 between the ring 16 and the wheel ange 9 normally maintainthe ring 16 and the wheel flange 9 in prede- 20 termined spaced -relation to each other.

The brake drum 6| of the wheel I1 is adapted l"o be engaged at will by a pair of linedbrake shoes mounted in variable relation thereto in a manner similar to the mounting of brake shoes 66 and 61 of the wheel I6. In Fig. 1, for example, I have shown the brake shoe 83. constituting one of the pair of brake shoes for the wheel I1, hingedly mounted on the brake shoe mounting post 84 to which-it is securedby means of the nut 85. The brakeshoe mounting post 84 is affixed to a mounting plate 86 extending annularly outwardly from the axle housing The mounting plate 86 is formed with an axially ex'- tending concentric ilange 81 telescopically sealingly angaging'the brake drum 6| thereby to prevent the entrance of dirt, water or other foreign matter into the brake shoe chamber.

A ring 68 concentric with the axle I8 is carried by the mounting plate 86 for reciprocal movement axially of the wheel I1 by means of pins 89 extending through correspondingly located openings in the mounting plate. In the construction shown in Figs. 1 and 5, the pins 89 are ve in number, although more or less may be found necessary or feasible. 'I'he pins 89 are preferably located on a circle whose axis is concentric with the axis of the ring 68,. One end of each pin threadedly engages an annular flange 98 of a brake shoe operating ring surrounding the axle housing Il. Helical springs 92 encompassing the pins 89 between the flanges 86 and 98 normallyhold the ring 88 in the retracted position shown in Fig. 1.

The yoke arm 93 of bell crank lever 94 whose other arm 95 is pinned to a brake lever connecting rod 96 .is secured by means of pins 91 to the brake operating ring 9| whereby restricted axial movement of the brake .operating ring 9| can be obtained by movement of the connecting rod` 96.

A brake shoe spreader member 98 is pinned to the arm 99 of a bell crank lever |88 whose other arm |,8I is hlngedly connected by means of a link |82 with the ring 88.

AThe bell crankrlever |88 is hingedly mounted upon ashaft |85 located in a recess |83 in the mounting plate 86 so that the plane of the arms 99 and |8| extends -radially from the axis of the Thus, it will'be observed that the combination 75 and relationship 4of the parts constituting the brake mechanism is such that movement of the the connecting rod 86 to effect movement of bell crank lever 94, the brake operating ring 9| will be moved axially `outwardly to eil'ect a corresponding axial outer movement of the pins 89 against the resistance oil'ered bythe springs 92. The pins 89 carry with them in their outer movement the ring 88 which, in turn, through' the medium of the link |82 and the bell crank lever |88 effects a displacement of the spreader barv 98 lcausing the brake shoe 83 (and its mate not shown) to be pressed againstthe brake drum 6| therebyto retard or stop rotation of the wheel I1.

After the ring 88 is moved axially outwardly to apredetermined distance, it comes into contact with the anti-friction rollers 11 of the brake actuating ring- 16. Further movement of the ring 88 causes axial outwardmovement of the ring 16 against the resistance oiered by the springs 82. This movement of the ring 16 is communicated through the pin 88 to the arm 15 of the bell crank lever 12 which latter is moved angularly about its axis 13. 'Ihis angular movement is transmitted by the arm 14 to thespreader member 1| which, in turn, through the links 69 and 18 effects angular displacement of the brake shoes 66 and 61 about the brakeshoe support members 62 and 63 into engagement with the brake drum 68 thereby to retard or stop rotation of the wheel 68 about its axis.

As the braking force is removed from the brake lever connecting rod 96, the rings 16 and 88 will be moved axially inwardly and ultimately returned to their normal inoperative ,positions shown in Fig. 1 by means of thesprings 82 and 92 respectively. The .spacing between the rings 16 and 88 is normally such that braking eiort will be transmitted to the wheel |1 before being transmitted tothe wheel I6. The amount of this lag in application of the braking eil'ort is controllable by adjustment of the nuts 8| on the lugs 18 of the ring`16 so as to provide more or less space between the rings 16v and 86 in their normal inoperative positions. The greater the distance between the two rings, the more will be the lag in the application of the braking eiort to the'wheel I6. Conversew, the closer the'two' rings are to each other in their normal inoperative position, the less will be vthe lag in the application of the braking force of the wheel I6. Obviously, if the rings are touching in their normal operating position, thebraking eiort will be applied simultaneously and equally to both of .t the, wheels.

thereto, and in which both wheelelements may I optionally be allowed to rotate relative to eachother and to the driving axle; I have provided a novel braking construction for such a dual wheel unit by means of which a braking eiort can be applied to the wheel elements whether they are rotating freely or are being driven as a unit or arel rotating relative to each other; I have provided a novel braking construction for .such a aaaaaae 5 wheel unit by means of which the wheel elements may be progressively braked without regard to whether the wheel elements are beingv driven separately or are rotating relative to the torque applying means; and, I have provided a novel mechanical movement for multiple wheel units, differential mechanisms, systems for transmitting mechanical power and the like, capable of transmitting torque from one to the other of a pair of rotatably mounted elements in either direction of rotation thereof but vincapable of transmitting torque from the latter to the former. It will be observed that certain features and sub-combinations of my invention are of utility and may be employed without reference to other features and`sub-combinations thereof. This is contemplated by and is within the scope of the appended claims. It is further obvious that various changes may be made in details within the scope of the appended claims without departing from the spirit of this invention., It is, therelatter element, and by angular acceleration ofsaid latter element relative to said former element, said member may be caused to pivot upon its axis out of said position of driving engagement; and, means opposing pivotal movement of said driving memberinto said driving position.

2. The combination with rotatably mounted elements of a coupling device therefor comprising locking members so mounted pivotally upon one of said elements that by angular acceleration of said element relative to another of said elements, said members may be caused to pivot upon their respective axes into a position of driving engagement with said latter element, and by angular acceleration of said latter element rela- -tive' to said former element, said members may be caused to pivot upon their respective axes out of said position of driving engagement; and,

means connecting said members for causing said members to pivot together.

wise or counter-clockwise direction, said member may be causedto pivot upon its axis into a position of driving engagement-with said latter element, and by angular acceleration of said latter element relative to said former element while said. elements are rotating in either a clockwise or counter-clockwise direction, said member may be caused to pivot upon its axis out of said position of driving engagement.

5. Vehicle running gear comprising a driving axle; means forming a driving member extending radially outwardly from said axle and rotatable therewith; a vehicle wheel at either side of said driving member, said wheels and axle having a common axis and being relatively rotatable; a locking member at either side of said driving member, said locking members respectively being adapted to engage the hub of the corresponding wheel, said locking members respectively being mounted on said driving member for movement pivotally thereof upon Van axis parallel to 'and spaced from said common axis, said locking members respectively having an engaging surface of symmetrical contourwhose radius of curvature is greater than the distance from the pivotal axis of the locking member to the hub of the wheel adapted to be engaged by said locking member; and, means opposing pivotal movement of said locking members into said locking position.

6. Vehicle running gear comprising a driving axle; a sleeve member coaxially aligned and rotatable with `said axle; a driving disc integral with said sleeve member, said drivingdisc being located intermediate the ends of and coaxial with said sleeve member; a wheel journaled upon said sleeve member at either side of said driving disc; a locking member mounted on said driving disc at either side thereof for movement pivotally thereof upon an axis constituting an element of a cylindrical surface of revolution coaxial with said axle, each said locking member having a cam sur- 3. The combination with rotatably mounted elements of a coupling device therefor comprising locking' members so mounted pivotally upon one of said elements that by angular acceleration of said element relative to another of said elements, said members may be caused to pivot upon their respective axes into a position of driving engagement with said latter element,` and by angular acceleration of said latter element relative to said former element, said members may be caused to pivot upon their respective axes out of said position of driving engagement, means connecting said members for causing said' membersto pivot together; and, means acting upon said connecting means for opposing pivotal movement of said members int`o said driving position. r

. 4. The combination with rotatably mounted elements of a coupling device therefor comprising a locking member so mounted pivotally upon one of said elements that by angular acceleration of said element relative to another of said elements while said elements are rotating in either a clockface o! circular contour adapted upon angular displacement of the locking member uponl its pivotal. axis in either a clockwise or counterclockwise direction from a neutral position to engage the hub of one of said wheels thereby to lock the said wheel and said driving disc to each other for rotation as a unit, each said cam surface having a radius of curvature greater than the radius of curvature of the circle of oscillation ofthe said locking member; and, means for yieldingly opposing angular displacement of each said locking member upon its axis.

7. Vehicle running gear comprising a 'driving axle; a sleeve member coaxially aligned with and rotatable with said driving axle; a driving disc integral with said sleeve member, said driving disc being located intermediate the ends of and coaxial with said sleeve member; a wheel journaled upon said sleeve member at either side oflsaid driving disc; locking members mounted on said driving disc at either side thereof for move-- ment pivotally thereof upon axes constituting elements of a cylindrical surface of revolution coaxial with said axle; each Asaid locking member having a symmetric cam surface adapted upon angular displacement of the said locking member upon its pivotal axis in either a clockwise orv member having locking members pivotally mounted on said coaxial member, said locking positioned between their pivot and the cylindrical member so that'by angular acceleration o! one of said elements relative to another of said elements, said member may be caused to pivot upon its axis into a position of driving engagement with said latter element, and by angular acceleration ofsaid-latter element relative to said former element, said member may be caused to pivot upon its axis out of said position of driving members having eccentric faces to engage said 10 engagement.

cylindrical member, said eccentric faces being JOHN DARBY. 

